xlib: Create an exact match for the image surface if possible using Xrender

In order to defer the pixel conversion till as late in the pipeline as
possible, we want to try and preserve the pixman image format whilst
uploading the pixel data. To do this, we want to create an XRender
surface with a matching PictFormat to the source image. Then we need to
make sure we take the quick path through _draw_image_surface for none
and direct conversions.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 91 insertions, 20 deletions

diff --git a/src/cairo-xlib-surface.c b/src/cairo-xlib-surface.c
index 1747be213..85852086c 100644
--- a/src/cairo-xlib-surface.c
+++ b/src/cairo-xlib-surface.c
@@ -1157,6 +1157,7 @@ _draw_image_surface (cairo_xlib_surface_t   *surface,
     pixman_image_t *pixman_image = NULL;
     cairo_status_t status;
     cairo_bool_t own_data;
+    cairo_bool_t is_rgb_image;
     GC gc;
 
     ximage.width = image->width;
@@ -1176,7 +1177,26 @@ _draw_image_surface (cairo_xlib_surface_t   *surface,
     if (unlikely (status))
         return status;
 
-    if (!_pixman_format_to_masks (image->pixman_format, &image_masks))
+    is_rgb_image = _pixman_format_to_masks (image->pixman_format, &image_masks);
+
+    if (is_rgb_image &&
+	(image_masks.alpha_mask == surface->a_mask || surface->a_mask == 0) &&
+	(image_masks.red_mask   == surface->r_mask || surface->r_mask == 0) &&
+	(image_masks.green_mask == surface->g_mask || surface->g_mask == 0) &&
+	(image_masks.blue_mask  == surface->b_mask || surface->b_mask == 0))
+    {
+	int ret;
+
+	ximage.bits_per_pixel = image_masks.bpp;
+	ximage.bytes_per_line = image->stride;
+	ximage.data = (char *)image->data;
+	own_data = FALSE;
+
+	ret = XInitImage (&ximage);
+	assert (ret != 0);
+    }
+    else if (!is_rgb_image ||
+	     (surface->visual == NULL || surface->visual->class == TrueColor))
     {
         pixman_format_code_t intermediate_format;
         int ret;
@@ -1217,21 +1237,6 @@ _draw_image_surface (cairo_xlib_surface_t   *surface,
 	ret = XInitImage (&ximage);
 	assert (ret != 0);
     }
-    else if ((image_masks.alpha_mask == surface->a_mask || surface->a_mask == 0) &&
-             (image_masks.red_mask   == surface->r_mask || surface->r_mask == 0) &&
-             (image_masks.green_mask == surface->g_mask || surface->g_mask == 0) &&
-             (image_masks.blue_mask  == surface->b_mask || surface->b_mask == 0))
-    {
-	int ret;
-
-	ximage.bits_per_pixel = image_masks.bpp;
-	ximage.bytes_per_line = image->stride;
-	ximage.data = (char *)image->data;
-	own_data = FALSE;
-
-	ret = XInitImage (&ximage);
-	assert (ret != 0);
-    }
     else
     {
 	unsigned int stride, rowstride;
@@ -1467,6 +1472,73 @@ _cairo_xlib_surface_same_screen (cairo_xlib_surface_t *dst,
     return dst->screen == src->screen;
 }
 
+static cairo_xlib_surface_t *
+_cairo_xlib_surface_create_similar_for_image(cairo_xlib_surface_t *other,
+					     cairo_image_surface_t *image,
+					     int width, int height)
+{
+    XRenderPictFormat *xrender_format;
+    cairo_xlib_display_t *display;
+    cairo_xlib_surface_t *surface;
+    cairo_status_t status;
+    Visual *visual;
+    Pixmap pix;
+
+    /* Try to create a surface using an xrender format that exactly matches
+     * the image data so that we can upload the pixels and perform any
+     * conversion on the GPU.
+     */
+
+    if (!CAIRO_SURFACE_RENDER_HAS_CREATE_PICTURE (other)) {
+fallback:
+	return (cairo_xlib_surface_t *)
+	    _cairo_xlib_surface_create_similar (other,
+						image->base.content,
+						width, height);
+    }
+
+    status = _cairo_xlib_display_acquire (other->base.device, &display);
+    if (unlikely (status))
+	return (cairo_xlib_surface_t *) _cairo_surface_create_in_error(status);
+
+    if (image->format != CAIRO_FORMAT_INVALID)
+	    xrender_format =
+		_cairo_xlib_display_get_xrender_format (display, image->format);
+    else
+	xrender_format =
+	    _cairo_xlib_display_get_xrender_format_for_pixman (display,
+							       image->pixman_format);
+    if (xrender_format == NULL) {
+	cairo_device_release (&display->base);
+	goto fallback;
+    }
+
+    pix = XCreatePixmap (display->display, other->drawable,
+			 width, height, xrender_format->depth);
+
+    if (xrender_format == other->xrender_format)
+	visual = other->visual;
+    else
+	visual = _visual_for_xrender_format(other->screen->screen,
+					    xrender_format);
+
+    surface = (cairo_xlib_surface_t *)
+	_cairo_xlib_surface_create_internal (other->screen, pix, visual,
+					     xrender_format,
+					     width, height,
+					     xrender_format->depth);
+
+    if (unlikely (surface->base.status)) {
+	XFreePixmap (display->display, pix);
+	cairo_device_release (&display->base);
+	return surface;
+    }
+
+    surface->owns_pixmap = TRUE;
+    cairo_device_release (&display->base);
+    return surface;
+}
+
 static cairo_status_t
 _cairo_xlib_surface_clone_similar (void			*abstract_surface,
 				   cairo_surface_t	*src,
@@ -1498,10 +1570,9 @@ _cairo_xlib_surface_clone_similar (void			*abstract_surface,
 	if (width > XLIB_COORD_MAX || height > XLIB_COORD_MAX)
 	    return UNSUPPORTED ("roi too large for xlib");
 
-	clone = (cairo_xlib_surface_t *)
-	    _cairo_xlib_surface_create_similar (surface,
-						image_src->base.content,
-						width, height);
+	clone = _cairo_xlib_surface_create_similar_for_image(surface,
+							     image_src,
+							     width, height);
 	if (clone == NULL)
 	    return UNSUPPORTED ("unhandled image format, no similar surface");